The disclosed embodiments of the present invention relate to generating output video pictures (sequence) to a display apparatus, and more particularly, to a video processing apparatus capable of generating output video pictures (sequence) with a color depth different from a color depth of an encoded video bitstream.
Generally speaking, a color depth or bit depth is the number of bits used to indicate the color of a single pixel in a video frame. Hence, the video frame with a higher color depth setting would have a broader range of distinct colors. The 8-bit color depth is conventionally used by many video standards. However, with the development of display apparatuses such as liquid crystal display (LCD) apparatuses, the display apparatuses are capable of supporting higher color depths such as a 10-bit color depth, a 12-bit color depth and a 16-bit color depth. Hence, new video standards supporting color depths higher than the 8-bit color depth are proposed correspondingly.
However, it is possible that a conventional display apparatus which only supports a lower display color depth is still used by the user. When the video content carried by an encoded video bitstream with a higher color depth setting is to be displayed on the display apparatus supporting a lower display color depth, the encoded video bitstream should be processed by a video processing apparatus for properly generating output video pictures (sequence) to the display apparatus. For example, a conventional video processing apparatus may decode and process the encoded video bitstream under a higher color depth mode to obtain preliminary video pictures (sequence), and then generate the output video pictures (sequence) with a lower color depth setting by truncating the preliminary video pictures (sequence) with the higher color depth setting to satisfy the display color depth requirement of the display apparatus. Though the display apparatus is driven by the output video pictures (sequence) with the lower color depth setting, most circuit elements in the conventional video processing apparatus are required to operate in the higher color depth mode, which results in computing resource overhead and unnecessary power consumption.